hd 44195: a hybrid star with delta scuti and gamma doradus character
DESCRIPTION
HD 44195: a hybrid star with Delta Scuti and Gamma Doradus character. Molnár László Hungarian CoRoT Day Budapest 2007. Secondary COROT target on the field of HD 43587 (Anticenter Direction) Possible hybrid star δ Sct and γ Dor pulsation Strong constraints on stellar structure models. - PowerPoint PPT PresentationTRANSCRIPT
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HD 44195: a hybrid star with Delta Scuti and Gamma Doradus character
Molnár LászlóHungarian CoRoT Day
Budapest 2007
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HD 44195
Secondary COROT target on the field of HD 43587 (Anticenter Direction)
Possible hybrid star δ Sct and γ Dor pulsation
Strong constraints on stellar structure models
Sp: F0, unenvolved mV = 7.56 mag
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Hybrid stars
HD 44195
δ Sct: low-order p-mode pulsations (κ-mechanism)
γ Dor: high-order g-mode pulsations (convective blocking)
other hybrid stars: HD 209295(?), HD 8801
BD+18 4914, HD 114839 (MOST)
δ Scuti stars
γ Dor stars
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Previous observations
2003 nov. 2005.jan.
f < 5c/d f < 5c/d γ Dor γ Dor
f = 20.5 c/d f = 20.5 c/d δ Sct δ Sct
Poretti et al. 2005 AJ, 129, 2461
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Hungarian observations
1 m RCC telescope
2006 winter 8 nights, 39.4 hours
2007 winter 3 nights, 11 hours
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The γ Doradus frequencies
Poor sample
Solutions with 2 frequencies:
1
2
3
1.15 c/d 20 mmag 2.31 c/d 10 mmag
1.20 c/d 9 mmag 1.33 c/d 11 mmag
0.71 c/d 16 mmag 1.23 c/d 7 mmag
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δ Scuti frequencies
2006 winter data:
Changes to Poretti
et al.’s frequencies
Frequency (c/d) Ampl. (mmag)
20.48 2.3
11.40 2.1
15.37 1.4
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δ Scuti frequencies
All data Strong alias structure
Further changes?
Frequency (c/d) Ampl. (mmag)
11.35 2.5
15.32 1.5
20.48 1.9
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Hungarian vs. COROT data
Artificial data: 150 days long, no noise
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HD44195 - Summary
HD 44195 shows both γ Dor and δ Sct type frequencies
γ Doradus: at least 2 frequencies under 3 c/d δ Scuti: F1 = 20.5 c/d, F2 = 11.4 c/d, F3 = 15.3 c/d
Possible changes?
COROT will find out!
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HD 172189
Eclipsing and spectroscopic binary (P=5.7 days) Delta Scuti component 3 frequencies around
18-19 c/d
secondary target Hungarian observations: 2 nights (2006 summer)
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HD 172189
We have not observed eclipses Good agreement with the lightcurve
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Thank you for your attention